Bleaching is a critical textile wet process that is commonly required for removing yellowish natural impurities from cotton fibers prior to dyeing and finishing. One of the most common bleaching methods for cotton fibers utilizes hot hydrogen peroxide bleaching under alkaline conditions. This process, however, is energy intensive and can chemically damage the cotton fibers.
Bleach activators are peracid precursors, which generate peracids in situ in the presence of hydrogen peroxide and alkali during a bleaching process. Typically, peracids are more reactive bleaching species than hydrogen peroxide and therefore can be used for bleaching at reduced temperatures. Bleach activators can be used in a variety of applications, including, but not limited to, home and industrial laundry usages, see A. P. James and I. S. MacKirdy, Chem. Ind., 15 (1990) 641; K. Grime and A. Clauss, Chem. Ind., 15 (1990) 647; and R. J. McLean, Text. Chem. Colorist Am. Dyestuff Rep., 1 (1999) 42, and industrial textile preparation processes, see S. J. Scarborough and A. J. Mathews, Text. Chem. Colorist Am. Dyestuff Rep., 32 (2000) 33; J. Y. Cai et al., AATCC Rev., 1 (2001) 31; and J. Wang and N. M. Washington, AATCC Rev., 2 (2002) 21. Nonanoyloxybenzene sulfonate (NOBS) and tetracetylethylenediamine (TAED) are two of the most widely used commercial bleach activators.
Cationic bleach activators provide affinity for the negatively charged surface of cotton in an aqueous solution and offer increased bleaching efficiency when compared to anionic bleach activators. Cationic bleach activators can be applied in a cold pad-batch and a hot peroxide bleaching process of cotton. See S. Lim, N. C. Gürsoy, P. Hauser and D. Hinks, Color. Technol., 120 (2004) 114. In particular, N-[4-(triethylammoniomethyl)benzoyl]caprolactam chloride (TBCC) has been shown to exhibit satisfactory bleaching performance in a shorter time and at lower temperatures than conventional peroxide bleaching. Id. In some cases, however, cationic bleach activators, such as TBCC, are unstable and can be readily hydrolyzed in aqueous solution. Such instability in aqueous solution is a significant drawback in industrial applications in which the cationic bleach activator cannot be stored in aqueous solution even for a short period of time. See J. J. Lee, S. Lim, P. Hauser and D. Hinks, Color. Technol. 121 (2005) 37. Thus, there is a long-felt need in the art for cationic bleach activators that are stable in aqueous solutions, while providing satisfactory bleaching performance.